Angular coil-spring



S. L.- MARKHAM.

ANGULAR COIL SPRING.

APPLICATION FILED -ov.5.191a.

- 1,349,079. Patented Aug. 10,1920

n a a a ll .72 i i f Y A i 'u'l'l'ln Hf Q 1 9 PATENT OFFICE.

SIDNEY L. MARKHAIM, OF JAMESTOWN, NET/V YORK.

ANG-ULAR GOIL-SPRING.

Application filed November 5, 1918.

To all whom it may concern Be it known that I, SIDNEY L. MARKHAM, acitizen of the, United States, residing at the city of Jamestown, in thecounty of Chautauqua and State of New York, have invented certain newand useful Improvements in Angular Coil-Springs, of which the following,takenin connection with the accompanying drawings, is a specification.

The invention relates to coil springs. In the formation of coil springsa highly beneficial quality of such a spring is one in which the springis instantly active under stress throughout its entire length andparticularly when said spring is used with tor sional strain, also toincrease the torsional power of the spring without impairing its otherqualities.

' The object of the improvement is to provide a coil spring having acontinuous succession of alternating angular bends and straight portionsor legs in the wire coil whereby the torsional strength and activity ofthe spring is greatly increased and the other qualities of the springare enhanced including the appearance of the spring; and the inventionconsists in the novel features and combinations hereinafter set forthand claimed including the method of making said coil spring. 7

In the drawings, Figure 1 is a perspective view of an angular mandrelwhich is quadrilateral in cross section with wire coiled thereon to makethe improved form of coil spring, the mandrel being shown spirallytwisted. Figs. 2 and 3 are side and, end elevations of the angular coilspring removed from the mandrel showing the manner in which the springof the wire causes the coil spring to spring outwardly from the mandrelwhen released therefrom thereby bringing the angular bends midway 0f thelength of the adjacent straight portions or, as it were, causing saidangular bends to break oints alternately with said straight portionsthroughout the length of the wire in said spring coil, the end elevationin Fig. 3 showing the pentagonal form which the wire coil assumes whenreleased from the quadrilateral shaped mandrel. Fig. 4 is a detail ofone of the bends in the spiral coil showing the straight leg each sideof said bend. Fig. 5 is a perspective view of a straight sided angularmandrel which is qualrilateral in cross section showing the manner ofwinding the wire thereon with Specification of Letters Patent.

Patented Aug. 15?, 1920.

Serial No. 261.278.

the slotted end for holding the end of the wire in starting the wind;and Fig. {l is an elevation of an angular mandrel which is quadrilateralin cross section as clamped in a chuck for winding the wire thereon in ama'chinists lathe or similar device. Fig. 7 is a perspective view of atriangular mandrel with the wire wound on the same, said mandrel beingshown spirally twisted, and Figs. 8 and 9 show side and end elevationsof the wire coil removed from the triangu mandrel showing the angularsl' ape into which the wire coil springs when released from its closewinding tension on said triangular mandrel. Fig. 10 is a crosswisesectional view of a pentagonal shaped mandrel; and 11 is an endwise viewof the hexagonal form into which the spiral coil springs or relaxes whenreleased from the close winding tension on the pentagonal shapedmandrel.

Like characters of reference refer to corresponding parts in the severalviews.

The numeral 10 designates a straight sided mandrel which isquadrilateral in cross section; and the numeral 11 designates a mandrelwhich is spirally twisted and is quadrilateral in cross section withslightly concave sides, which maudrels are used to coil my improvedspring thereon.

The spiral twisting of the mandrel gives a slightly easier release tothe coiled wire and is more apt to insure the angular bonding of thecoiled wire 19 in regular succession. Either form of mandrel 10 or 11however will attain my purpose.

The improved coil spring consists of a succession of substantially equalstraight legs or coil sides 13 separated by angular bends 12, that is,the angular bond 12 has a straight coil side or leg 13 each sidethereof, the bends 12 being at such an obtuse angle as to form a manysided coil, in which by my process of construction the angular bends l2occur midway of the length of the straight sides 13 in the adjacentcoils. Said straight sides 13 act as levers to which the angular bends12 provide a fulcrum so that there is a continuous series of levers andfulcrums provided throughout the length of the coiled wire so thatsubstantially any torsional strain upon any part of the spring iscommunicated to the remainder thereof. Thus, for example, a torsionalstrain at one end is almost instantaneously felt at the opposite end ofthe spring.

7 same.

V The method of, making this improved .coil spring with its successionof angular bends 12 and straight sides 13 consists in mounting amandrel, angular shaped in cross-sectiomso that it may be rotated andproviding means for the rotation of the Also providing means for theprogressive feeding of the wire on to the rotating mandrel. The angularmandrel is for most springs preferred in, the straight form shown inFig. 5 and may have as many sides 141 as it is desired to have coilsides 13 in the coil spring except that the mandrel should have one lessside than the desired coil spring since the wire 19 is wound onthejangular mandrel under tension so that it is drawn firmly across thecorners 15 of the mandrel thereby forming the angular bends 12 andproviding the straight sides 13 in the angular coil.

The sides 14: of the angular mandrel may be flat as shown in Figs. 5 and6 or having a slight concavity so that the edges or corners 15 projectand give a slightly sharper angular, corner 12 for the coil. Thus whenit desired to have a pentagonal sided spring as shown at 16 in Figs. 2and 3 a quadrilateral shaped mandrel 10 or 11 is used and when a foursided spring is desired as shown at 17 a triangular shaped mandrel isused as shown in Fig. 7 or when a substantially hexagonal or six sidedspring is desired as shown at 18 in Fig. 11 a pentagonal shaped mandrelis used as shown in .Fig. 10.

In order to wind the springs in; perfect coil alinement the mandrels arepreferably provided with an open slot 21 in the end thereof into whichthe angularly bent end 20 is inserted to start the coil. A closed slot22 may used though it is not quite so easy of insertion as the openended slot 21. The angular mandrel is preferably placed in a chuck 23which will firmly hold the same and inserted in a machinists lathe orsimilar device so that the mandrel 10 or 11 may be rotated at a givenspeed. Such a lathe or'machine provides means for the progressivefeeding of the wire 19 onto the rotating mandrel 10 or 11 under tensionso that it is drawn firmly across the corners 15 of the mandrellO orllthereby forming the angular bends 12 in regular succession between thestraight sides 13.

It is usually preferable however to wind the wire 19 with a small amountof temper so that while under said tension the mandrel may be turnedbackward on the wrapped wire about'one-third of a turn or until the coilreleases from the mandrel thereby easing the release of said wire andangular coil spring than the'mandrel upon which it is wound.

'This spiral arrangement of the alternating angular bends l2 andstraight sides 13 gives a pleasing appearance or design to the springcoil.' At the same time the tor-- sional. strength of the coil islargely in creased and the torsional activity is correspondinglyincreased; Indeed there is no office which a coil spring can perform inwhich the action of the angular coil spring is, not an improvement onaccount of its greater activity or rapidity of action.

I claim as new 7 l. A torsional-spring composed of a series ofcontacting coils closely wound under tension, each coil consisting of aseries of straight sides joined by bends, the bends of adjacent coilsbeing uniformly offset to maintain the general cylindrical shape of acoiled spring. 7

2. A torsional spring composed of a series of closely wound contactingcoils of polygonal shape, said coils wound under tension sufficient touniformly and progressively stagger the bends of the coils relative toone another whereby the periphery of the generally cylindrical springwill be provided with spiral series of projections.

In testimony whereof I have affixed my signature in the presence of twowitnesses.

SIDNEY L. MARKHAM.

Witnesses:

- H. A. SANDBERG,

A. WV. KEITH.

